Effect on South American CL: This
would revise generic boundaries extensively in Buteogallus, Leucopternis,
and related genera.

Background
& New Information:For several years, we’ve had plenty of
indication that the current boundaries of genera in the vicinity of Buteogallus in our current
classification are a mess.Raposo
do Amaral et al. (2009) have produced a comprehensive phylogeny of buteonine
hawks, and their data will form the primary basis for this proposal.Findings from earlier papers (see Notes
below) are largely consistent with Raposo do Amaral et al. (2009) and will not
be discussed further.Two of the
relevant Notes from our SACC classification are:

14b. Buteogallus
urubitinga was formerly treated in the monotypic
genera Urubitinga(e.g., Hellmayr &
Conover 1949) or Hypomorphnus (Pinto 1938, Friedmann 1950, Phelps
& Phelps 1958a), but see Amadon (1949) and Amadon
& Eckelberry (1955) for rationale for placement in Buteogallus.
Genetic data (Lerner & Mindell 2005), however, indicate that Buteogallus
urubitinga and B. anthracinus are not sisters and that the former is
more closely related to Harpyhaliaetus (see also Amadon 1949, Raposo et
al. 2006). Raposo do Amaral et al. (2009) recommended that they be treated in
the genus Urubitinga.Proposal badly
needed.

Raposo do
Amaral et al.’s (2009) taxon sampling (105 specimens, 54 species) and gene
sampling (6000 bp of 9 genes, mitochondrial and nuclear) is exemplary.I doubt that anyone will produce a
better data set anytime soon.This
proposal deals only with their Group H, whose monophyly has excellent support;
the relevant portion of their tree (from their Fig. 3) is pasted in here:

Therefore, the
problems in current classification are even worse than revealed in earlier
papers, with most species requiring a change in genus.Raposo do Amaral et al. had to name two
new genera to avoid combining all species into one large, heterogeneous Buteogallus.The latter solution is actually an
alternative to be explored if this proposal does not pass.Group H includes all the taxa previously
associated with Buteogallus, within
which generic limits have been historically fluid, and adds in three species
from Leucopternis, two of which are
dark like most of the Buteogallus
group but also one (lacernulatus)
that has more typical black-and-white Leucopternis
plumage.What a mess.At least one of the former Leucopternis, schistaceus, has a riverine habitat like its new sister taxa, Buteogallus sensu stricto.

Analysis and Recommendation: Virtually every critical node in Group H’s tree has strong
support.Therefore, the only point
of real discussion is the subjective exercise of how broadly to delimit the
genera.Raposo do Amaral et al.
have defined these very narrowly, and as stated above, one option would to be
expand Buteogallus to include all
nine species in Group H.Even the
outlier, plumbeus, placed in a newly
described genus Cryptoleucopteryx,
has no single character that diagnoses it, but only a unique combination of
characters.I do not know enough
about voice and behavior of these birds to say anything about whether such a
broad genus would violate subjective notions of homogeneity in currently
circumscribed hawk genera, but my first instinct is that it wouldn’t be any
more heterogeneous than even a narrowly defined Buteo.

If we adopt as
is the Raposo do Amaral et al. classification, the linear sequence would look
like this:

I do not know
the former Harpyhaliaetus species
well, but I have reservations about placing Great Black Hawk and Solitary Eagle
in same genus if they are to be narrowly defined – why not just retain Harpyhaliaetus?Using just genetic distance suggests
that it as roughly as distinct from Urubitinga
urubitinga as are the other genera in the proposed classification.

A YES vote
would be to adopt this classification as is.A NO vote would be to broaden generic
boundaries, from as little as reinstating Harpyhaliaetus
to as much as including everything in Buteogallus.If this proposal fails, I’ll write
additional proposals to take into account broader generic limits.I do not have a recommendation.Because delimiting genera is a
subjective exercise as long as each is monophyletic, I wait to hear from those
with more experience with these birds.Please help solicit such opinions.

Comments
from Stotz: “NOSomehow
the creation of 2 new genera and the use of 5 genera for a total of 9 species
seems like too much.My preference
would be for 1 genus or possibly 2 (Buteogallus
and Cryptoleucopteryx) for this
group.There are other treatments
that are possible up to 6 genera, but I think, given that the taxa we currently
treat in Buteogallus are scattered
from one end of the tree to the other, that just inserting all of those taxa
into Buteogallus is the way to
go.I am a little alarmed by Leucopternis lacernulatus being in the
middle of this, but otherwise this basically fits pretty well with my
intuition.”

Comments
from Bret Whitney: “In full agreement with Remsen
that “delimiting genera is a subjective exercise as long as each is
monophyletic”, the problem remains one of defining the boundaries of
“monophyly”. With little more to “guide” me beyond a feeling of comfort
within indefinable (for me) limits of similarity among species within the context
of natural histories and biogeographic speciation patterns... I’d be most
content with recognizing the (previously unsuspected, for me) close
relationshipof Buteogallus meridionalis and Leucopternis
lacernulatus with placement together in Heterospizias; and
recognition of the somewhat deeper (as I understand it?) split between the
close pair of Harpyhaliaetus solitarius + H. coronatus and Buteogallus
urubitinga by maintaining these two groups in separate genera: Harpyhaliaetus
and Urubitinga.”

Comments
from Robbins: “NO.Instead
of creating multiple genera (as Van points out this is similar to the broadly
defined Buteo; voice,plumage, & behavior is extremely
broad in that genus even within a single subcontinent), I would prefer
including everything in Buteogallus.”

Comments solicited from Fabio Raposo: “Thanks very much to Van and the committee for
requesting comments and letting us be part of this discussion. Van did a great
job translating our trees in this series of proposals. I agree that this is a
really messy (and difficult) group, and it took a lot of time and discussion to
end up with the classification that we proposed. A few important points:

- As
commented by Bret and Stotz, clustering of L. lacernulatus and B.
meridionalis was unexpected to us, too. L. lacernulatus is a black
and white forest species endemic to the Atlantic Forest of Brazil, while Buteogallus
meridionalis is a mostly brown/rufous, open-vegetation widespread species
of SA savannahs. This relationship is, however, very well supported. In
addition, all species in clade H are represented by at least one
vouchered muscle sample (including perhaps the only vouchered fresh muscle
samples of L. lacernulatus and H. coronatus in the world – skins
available at MZUSP). Furthermore, close relationship of L.
lacernulatus and B. meridionalis to species in clade H echoes two
previous papers, one of them performed by independent researchers (Amaral et
al. 2006; Lerner et al. 2008). Evolution acts in unpredictable ways, and one
possibility is that those two species represent relicts of once larger clades
affected by extinction, for example. We do not support their lumping in a
single genus exactly because of their high divergence in plumage, ecology
and evolutionary time, and for this reason we proposed the resurrection of Heterospizias
for B. meridionalis and the new generic name Amadonastur for L.
lacernulatus.

-
Contrary to the L. lacernulatus/B. meridionalis case, very close
resemblance of H. solitarius and B. urubitinga plumages (in some
aspects much closer than between H. solitarius and its sister H.
coronatus) has lead us to conclude that they would be better represented by
one genus. Please also compare, using figure 4 (see below why), divergence
between L. lacernulatus and B. meridionalis and divergence among
the three species that we propose to be in Urubitinga.

- Branch
lengths of Figures 1 and 3 should be interpreted with caution, since they may
have no meaning if one wants to consider divergence as a measure of time: the
data do not evolve in a clock-like manner. In other words, long branches may
not reflect long evolutionary time, and short branches do not necessarily
reflect short evolutionary time. If time may contribute to this
discussion, figure 4 would be more suitable (a relaxed-clock
analysis, that incorporates the variation in rates of molecular
evolution responsible for the violation of a strict molecular clock, and
includes very conservative confidence intervals). Interestingly, despite the
large confidence intervals, the genera as we proposed would split from the rest
of the tree approximately close in time (see nodes 47, 48, 50, 55, 57, 59 and
70).

- In any
case, many nomenclatural changes are necessary, and different schemes would
have similar effects (e.g. our proposal or any made so far would need from five
to six changes for clade H).

- Finally, if the idea is to
indicate phylogenetic relationships, broadly defined genera and monotypic
genera in practice are equally little informative. However, if using a few
monotypic genera (which are justifiable in cases
of divergent, autapomorphic species) makes it possible to
indicate so many morphologically homogeneous groups (as we believe to be the
case with Buteogallus and Urubitinga here - but
also see SACC 460), perhaps it makes less harm to have a few monotypic
genera than considering a lot of differences in large, undiagnosable and very
heterogeneous groups (as it would be in including clade H in Buteogallus, or
even worse, clade G in an extremely inclusive Buteo cited in proposal
460).But if we are to recognize
larger groups, it is crucial to define them in terms of diagnostic characters
and/or the most objective criteria as possible – i. e. it is always possible to
indicate (based on published data, of course, in terms of plumage
patterns, ecology, vocal characters, behavior, or any other criteria) why to
attach a name to a group of species. Only then we would have comparable
competing schemes, supported by concrete evidence.

Comments
from Zimmer: “NO.I’m okay
with some of the proposed Raposo do Amaral et al. classification, but not all
of it.And I really don’t like the
idea of throwing all of these birds into a heterogeneous Buteogallus.I think
there are good reasons why L. plumbea
shows up as an outlier in this classification.It is vocally very distinctive from
everything else, including regular indulgence in some pretty wild male-female
duets, in which the respective vocalizations of the male and female appear to
be sexually stereotypical.It also
seems pretty different ecologically from the others, in being a forest-interior
bird that doesn’t regularly soar.I’d really be inclined to put it in its own genus, as Raposo do Amaral
et al. have done.I’d also separate
out the two Harpyhaliaetus – they
form a distinctive pair, and I don’t see any real advantage in placing them in Urubitinga.Removing urubitinga from Buteogallus,
and moving schistaceus into there
makes perfect sense given the existing data.I’d be inclined to follow Raposo do
Amaral et al. in keeping meridionalis
and lacernulatus in separate genera
even though they are apparently sister taxa.Aside from plumage differences, there
are some pretty obvious structural, ecological and behavioral differences.Putting those two in the same genus
would make delineating other genera on the grounds of avoiding too much
heterogeneity hard to defend.”

Comments from Stiles:“YES. After
mulling over the proposed changes, I find myself in pretty complete agreement
with Fabio on this one.First,
having had the opportunity to observe the Solitary Eagle frequently in Costa
Rica, I was impressed with its vocal, morphological and behavioral similarity
to (B.) urubitinga and I fully support congeneric status for these two,
with (H.) coronatus along for the ride. Although I don’t know lacernulatus, everything I’ve read about
it makes me averse to including it in a genus with the totally different meridionalis, hence monotypic genera for
both seem best.I also don’t know plumbea but Kevin’s comments make
separate (monotypic) status for it palatable as well. “